Carrier-telegraph alarm system



March 4, '1930.

v.` P. THQRP ET Ax. CARRIER TELEGRAPH ALARM sYsTEu Filed March 6, 1928 INVENTORS gmzwhmea ATTORNEY v*Patented Mar. 4, 1930 UNITED STATES PATENT OFFICE 'VAUGHN P. T'HORP, OF RIVER EDGE, NEW JERSEY, AND WILTON T. REA, 0F FLUSH- ING, NEW YORK, ASSIGNORS TO- AMERICAN TELEPHONE AND TELEGRAPH COM- PANY, A CORPORATION OF NEW YORK CARRIER-TELEGRAPH ALARM SYSTEM Application filed March s,

This vinvention relates to carrier telegraph V circuits and more particularly to an improved alarm system for use with circuits ofthis type. f e

Thefalarm system of theinvention is designed to operate whenever a carrier telegraph ,circuit becomes open, grounded, or short circuited. The arrangements of the invention will notify the repeater attendants and `also the subscribers connected to such a circuit whenever theline fails so that an operator will not continue to send after the line is in trouble, not knowing that his signals are not being received. The arrangements of the invention will also automatically disable the sending apparatus ata station when the telegraph circuit failsf A further feature of the arrangements of the invention consists in the provision of restoring apparatus whereby aftery line failure, current will be intermitf tently applied to the circuit until the-fault thereon is repaired, whereupon the telegraph apparatus and the alarm arrangements will be restored to' normal. Other objects and features of the invention will appear more fully from the detailed description thereof hereinafter given.

The invention may` stood from the following description together with the accompanying drawing in the ligure yof which is illustrated a circuit diagram emifo.

bodying avpreferred form Vof the invention. Infthe drawing is shown a portion ofia carv rier telegraph systemcomprising the incomiing line section L1 and the outgoing line section Lg. Linesection L1r would bey connected to a receiving bus circuit'lG and line section L2 wouldbe connected toasending bus -cir.- cuit 15.'i Connected to then-receiving circuit y16'Wouldbe a plurality of carrier receiving channels. ChannelsAand'B and associated apparatus have Vbeen illustrated.Y Connections for otherchannels have also been shown. They receiving carrier channel A would include a filter FA, a detectorDA and a receiving relay 2. ySimilar apparatus would be included in the other receiving channels.v Connectedito the armature yof the receiving relay 2 Wouldbe areceiving legfA forchannel A. A portion of a sending leg 7A vfor this chanbemmore fully under- ,i

1928. Serial No. 259,521.

nel is indicated. Connected to the armature and the marking contact of the receiving relay of each channel would be a slow operate relay, such as the relay 4A and 4B. Connected to the contacts and armatures of all of the series 4 relays, such as 4A and 4B, is a circuit 9 which will have included therein the windings of a series of slow operate relays 5A and 5B. One of such relays will be provided for each channel. There is shown associated with the sending bus 15 a plurality of connections wherebyy different sending channels .may be connected to line section L2. Bridged across the sending bus 15 is a normally open short circuit 14 controlled by the disabling apparatus 24. The disabling apparatus 24 is controlled by the restoring arrangements 25, which will be described in more ydetail hereinafter.

, The arrangements of the invention operate in the following manner. When the line section Ll of the carrier telegraph system is functioning properly, carrier frequencies transmitted thereover will hold the receiving relays of the carrier'channels operated and their armatures will be held against their marking contacts. Under such conditions the series of slow operate relays, such as 4A and 4B will not operate. It is pointed out that these series 4 relays are sutliciently slow in operation so that they will notzbe affected of the receiving relays to release and to move their armatures to their spacing contacts. Under'such. conditions, batteries of av different polarity will be applied to the armatures of the receiving relays and the slow operate series 4 relays will be operated. When all of the series 4 relays 0perate,due tothe line fail-v ure, the circuit 9 will be completed. It is pointed out-that circuit 9 has included therein in series the armatures and contacts of all of the series 4 relays and hence it will not be completed unless all of the series 4 relays are operated. The circuit 9 will extend lfrom ground, winding of slow operate relay 5A, Contact and armature of relay 4A, and thence through the winding of the series relays of other channels and contacts and 'armatures of series 4 relays of other channels, as, for example, through kwinding of relay 5B and over contact and armature of relay 4B, and thence to conductor 9. From conductor 9 this circuit will be extended through the winding of relay y10, yto battery 11, and ground. The completion of this circuit will cause all of the series 5 relays, such as 5A and 5B to operate. The operation of relay 5A will disconnect the receiving leg from the armature of the receiving relay 2 and will connect the receiving leg over a conductor 8A- to the armature of the .break relay Quot shown). Under suchcon'ditions, if the sub# scriber' on channel A is sending, he will nowy receive his signals back again reversed. will indicate to him that the line', is in trouble. In a similar manner the other-,series 5i relays will connect the' receiving leg o'feach channel to the break relay armature of that channel to inform each operat'r'ir` of'triible on the line. Q

The aforementioned completion f circuit 9 will also, operate the relay 10. Tliisyvfill close the following circuit: from ground', winding of relay 12,' contact armature' of relay 10, conductor 17, contacts and armatures of relays 18 and 19,-'condiietor 20, arma# ture and contact of relay 10'; tofbatteryjll and ground.- This will operate the alar'h bell 13 and the relay 12. The opera-tion frelay 12 will close a short circuit 14 across the send-V ff ing'bus 15 and prevent'c'urreritfrin being sent over line L2 from the station. yhis will cause apparatus at the distant station sir'nilary tov that already describedv tov operate to notify each operator that the line isy in trouble and to disable'the'sending apparatus therea't.l

In order to prevent the apparatus ,aty stations from becoming locked up andV also in order to automatically Arestoreall the ar?" rangements to normal when the lineis re# paired, thev operating circuit for relay 12 is controlled by the restoring apparatus' 25 in the following manner.y The perating circuit for relay 12 was originally closed upon the,

operation of relay 10 and wasl completed over ythe contacts of relays 18'and *19 asp'reviously `pointed'out."The operation of relay 10 also closes thel following circuit: tery 11, contact and armature of relay 10,l con-A Yductor 20, winding of 'thermostatV relay21;,"v conductor26, contact and armature of relay 22, to ground. This will start to' heat up. the

winding of thermostat relay 21 and, an interval of approximately seconds, it will operate and connect g-roimd overits arma# ture, through the winding of relay 19v to coiiductors 28 and 20, armature andcontact of relay 10,Y and'thence to battery,-thereby operating relay 19. vIt islpointe'd out that the thermostaty relay 21 will havea certain slow release feature and `'Willfnot release forv approximately 5y seconds after its operating f y v19,V conductor 27, Winding lofrelay V22` to ground thereby operating relay 22. The operation of relay 22 will close a locking circuit Vfor itself, as follows: from battery 11,

armature and Contact of relayl 10, conductors 20 and 28", left hand armature and contact of relay 22, conductor 29,'right hand contactand armature of relay 1 8, conductors 30/and27, winding of relay22 to ground. According? ly, the relay 22 will remain operated after the relays21 and 19 release. Relay y21 'wil-l;

now startvto releaseI dueto'the fact that at its right hand armature' operation of ree" lay 22 will open the previouslytracedciw cuit for the thermostat relay 21. According? ly, after approximately seconds, the ther mostat relay 21 an'dthen the' relay 19 will release and again close the operatingeircluit for relay 12. This will stop the application ofV carrier current to line L22] The v`operation of relay 22 will in addition to 'closing the" lock l ing up circuit fer itself', close thev followingrv circuit: from battery 11, rightv hand armature and contact ofrelaylO, conductors 20l and 28,

winding of thermostat relay 23, Contact and Y rightvha'nd armature of relay 22to" ground. This Will start heating'iip the winding of thermostat relay 23 and after approximately 40 seconds, lsaid relay will operate and een# neet battery 11 over armature' and cintactl of relay 10, conductors 20 and 28, armati1re' and contact of relay 23, conductor 31,*to wind` ing of relay18 and ground, thereby operat-k ing relay 18. The operation of relay18`will open at its left hand Contact and armature the voperating circuit forA relay1-2,` tli,erefby'f p' releasing' relay 12 and allowing 'carrier can" rent to be applied out 'overline Lg tempo'rariiV ly. The operation of relay- 18will0pe'n ati'ts f right hand contact the `p'r'evio'usly ytra'ced locking circuit 'for relay 22 and will release', relay 22.V This willfopenthe' previously traced circuit kfor 'the thermostat" relay 28:3 Due 'to the slow release operation of relay 23, it willwnot release for approximately 51 seconds. At the end of such time, itwill rel lease and open thevc'ircuit-of relay18."4 Thisv will' release relay 18 and allow'- the operatingV circuit of relay 12 to be ''comlileted;.lagaimfy thereby preventing thev application of' car-If rier current to line L32. TheV above described cycles of operations will then, nbe yrepelated.;y

ies

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Accordingly, it will be se'enth`at"when the carrier line is in trouble andthe alarm` 'ap'pia' ratus operated, lthat carrier:current will beVV intermittently rapplied to the line fer'n ap-v proximately 5 kseconds atintervals of 40 secv defined by the appended claims.

What is claimed is:

l. A carrier telegraph system comprising a line circuit over which carrier currents are normally flowing, transmitting channels and receiving channels associated withv said line circuit, analarm circuit completed by the joint failure of all of saidy receiving channels y'due to an abnormal line circuit condition,

and means controlled by the completion of said-alarm circuit for intermittently disabling said transmitting channels.

2. A carrier telegraph system comprising a line circuit over which carrier currents are normally flowing, transmitting channels and receiving channels associated with said line circuit, an alarm circuit completed by the joint failure of all of said receiving channelspdue to an abnormal line circuit condition, means controlled by the completion of said alarm circuit for short circuiting the youtput of all of said transmitting channels,

and an automatic device controlled by ksaid c last mentioned means for intermittently opening and closing said short circuit.

8. A carrier telegraph system comprising aline circuit over whichl carrier currents are normally flowing, transmitting channels and receiving channels associated with said line circuit, an alarm circuit completed by the joint failure ofv all of saidk receiving channels due to an abnormal line circuit condition, means controlled by the completion of said alarm circuit for disabling all of said transmittingy channels, and an automatic device for periodically controlling said disabling apparatus controlled by the comple- Vtion of said alarm circuit.

termining the period of said intermittency` of control over said disabling apparatus.

5. A carrier telegraph system comprising a line circuit over which carrier currents are normally flowing, a plurality of sending channels and a plurality of receiving channels associated with said line circuit, slow operate relays associated with each of said receiving ychannels and operated thereby when an abnormal line circuit condition eX- ists, an alarm circuit completed serially over the armatures and contacts of all of said relays, and means controlled by the completion of said alarm circuit for intermittently disabling said transmitting channels.

In testimony whereof, we have signed our names to this specification this 5th day of March, 1928.

VAUGHN l?. THORP. WILTON T. REA.

4. A carrier telegraph system comprising a line circuit over which carrier currents are normally flowing, transmitting channels and receiving channels associated with said line circuit, an alarm circuit completed by the jointfailure of all of said receiving channels due to an abnormal line circuit condition, apparatus for. disabling allof said transmitting channels, and an automatic device controlledf bythecompletion of said alarm circuit for intermittently controlling said disabling apparatus, said automatic device comprlsing a circuit arrangement controlled by the operation of slow operate yrelays for de- 

